s1_generate_a_series_of_files() {
    for i in {1..100}; do
        echo "$i" > "/tmp/new_file$i"
    done
}
s2_list_4_files_in_long_format_about_account_and_group() {
    files=("/etc/passwd" "/etc/group" "/etc/shadow" "/etc/gshadow")
    for file in "${files[@]}"; do
        ls -l "$file"
    done | sort 
}
function s3_find_items_related_to_given_username() { 
    grep -h $1 /etc/{passwd,shadow} |sort -d
}
function s4_find_items_related_to_given_group_name() {
    local group_name=$1
        local files=(/etc/group /etc/gshadow)
        for file in "${files[@]}"; do
            grep -h "^$group_name:" "$file"
        done | sort
}
s5_create_group_for_given_group_names() {
    loacl group=("rnd" "itoperation")
    for group in "${group[@]}"; do
        groupadd "$group"
    done
}
s6_create_users_and_set_thier_group_as_required() {
    users=("adam" "bob" "calvin" "david" "edward")
    primary_groups=("users" "users" "users" "users" "users")
    supplementary_groups=("rnd" "rnd" "itoperation" "itoperation" "rnd")
    for i in "${!users[@]}"; do
        useradd -g "${primary_groups[$i]}" "${users[$i]}"
        usermod -aG "${supplementary_groups[$i]}" "${users[$i]}"
   done
}
s7_change_users_shell() {
    users=("adam" "edward")
    for user in "${users[@]}"; do
        usermod -s /usr/bin/sh "$user"
    done
}
s8_set_password_change_policy() {
    local usernames=("adam" "bob" "calvin" "david" "edward")
    for username in "${usernames[@]}"; do 
        chage -M 60 -m 10 -W 10 "$username"
    done
}
function s9_set_password_for_five_users() {
    usernames=(adam bob calvin david edward)
    for i in $(seq 1 5);do echo ${!i}:echo $(( $i-1));done
          echo "${username[0]}:$1" | chpasswd
          echo "${username[1]}:$2" | chpasswd
          echo "${username[2]}:$3" | chpasswd
          echo "${username[3]}:$4" | chpasswd
          echo "${username[$(( $i-1))]}:$5" | chpasswd
}
s10_lock_bobs_password() {
    passwd -l bob
}
function s11_include_adam_into_wheel_group(){
    usermod -a -G wheel adam
}
function s12_change_files_permission(){
    for i in {1..33};do chmod -R 640 /tmp/new_file$[3*i];done
} 
